UK-3 was launched from the Western Test Range in California by the US National Aeronautics and Space Administration (NASA) on Friday, 5th May, 1967. Now that it is in orbit the satellite is known as Ariel III. This is the third of a line of British satellites launched by NASA, and is the first in which the satellite itself is British built.
The launch vehicle was a four-stage Scout rocket, which projected the satellite into an orbit ranging between heights of 301 and 370 miles above the Earth, at a speed of approximately 17,000 mph. Useful results are expected to continue returning to Earth for two years.
Five organisations have mounted experiments in the satellite - the SRC Radio and Space Research Station, the Meteorological Office, and the Universities of Birmingham, Manchester and Sheffield.
The RSRS experiment aims to measure terrestrial noise. It is testing the capability of a system for monitoring global thunderstorm information, and will produce a world contour map relating noise levels to latitude and longitude for various times of day and season.
The Meteorological Office are making measurements of the vertical distribution of molecular oxygen in the Earth's atmosphere.
Birmingham University are running two experiments concurrently. Two probes are carried by Ariel III, which measure electron density and electron temperature alternately.
Manchester University, in the form of Jodrell Bank, have mounted an experiment with several objectives. They aim to measure the intensity of cosmic radio waves in the 2 to 4 Mc/s frequency range, to look for variations in intensity of cosmic noise as a function of time, and to investigate the H-field of noise bands in the ionosphere.
Sheffield University have mounted a VLF experiment which is working in conjunction with many ground observers, to investigate the output from many VLF radio stations.
Data is returned to Earth and recorded on magnetic tape at many tracking stations, notably those of the STADAN network, maintained by NASA, and other stations around the world. The Winkfield Tracking and Data Acquisition Station in Berkshire is one of the STADAN stations, operated jointly with RSRS.
Data is also recorded on a tape recorder in the satellite. When a command is received from a tracking station, the tape recorder plays back a burst of information from the experiments, and the satellite then automatically switches back to transmitting real time data. We therefore have two types of information received on tape at the tracking stations, that from the tape recorder being called low speed data, and the real-time data is 'high speed'. These analogue tapes are then transported to RSRS at Slough, who use a special digitising machine to transcribe them to IBM-compatible ½in digital tapes.
The first stage in the data reduction is performed on the IBM 7030 (Stretch) computer at AWRE Aldermaston. This stage is primarily concerned with the detection {and where possible correction) of formatting and data errors, but some calculations, monitoring services and indexing are also carried out. The output from Stretch is in the form of another ½in tape, which is sent to the Atlas Laboratory for the next stage of processing. The Laboratory, using a program written by AWRE under contract to the Space Research Management Unit (SRMU) of the SRC, undertakes the processing of these tapes, which usually number about 3 per week, into forms suitable for use by the experimenters, adding useful information such as the orbital position calculated from elements supplied by RAE Farnborough.
RSRS receive 1in tapes as a result of this, which they process further at Chilton, using the SC4020 plotter to produce graphs of their results.
For the Meteorological Office, who have a KDF9 computer, and can only process ¾in tapes, we have to produce a ½in tape, which is further transcribed to a ¾in tape by AWRE.
For Birmingham University, we produce a ½in tape, which they take to Birmingham, where they analyse the results on another KDF9 computer, this one being supplied with a ½in tape deck.
Manchester University are provided with 1in tapes, which they process on the Manchester Atlas computer.
Sheffield University perform their further processing at Chilton, and are therefore provided with 1in tapes. They also use the SC4020 to produce their results in an easily-used visual form.
The whole project has been a large exercise in co-ordination, both on the experimental side, which has been the responsibility of SRMU, and in the data reduction. The Atlas Laboratory has given considerable advice on the general problems of the writing of the programs to be run on Atlas, and is now involved heavily in the day-to-day production of the experimenters' tapes.
